4
producer surplus worker surplus The competitive market maximizes the total gains from trade accruing to the economy. efficient allocation: the allocation of persons to firms that maximizes the total gains from trade in the labor market.

5
If workers were mobile and entry and exit of workers to the labor market was free, then there would be a single wage paid to all workers. The allocation of workers to firms equating the wage to the value of marginal product is also the allocation that maximizes national income (this is known as allocative efficiency). The invisible hand process: self-interested workers and firms accomplish a social goal that no one had in mind, i.e., allocative efficiency.

6

7
The single wage property of a competitive equilibrium has important implications for economic efficiency. The allocation of workers to firms that equates the value of marginal product across markets is also the sorting that leads to an efficient allocation of labor resources.

8

9
NAFTA created a free trade zone in North America. Free trade reduces the income differential between the United States and other countries in the zone, such as Mexico. Total income of the countries in the trade zone is maximized as a result of equalized economic opportunities across the countries in the zone.